Why there are no max_wal_receivers

Hello :

I found that for PG9.2.4, there is parameter max_wal_senders,

But there is no parameter of max_wal_receivers.

Is that to say, that If max_wal_senders are 3.

Then 3 wal_senders will be activated ,

And then on the standby server, there will be 3 "receivers" for
counter-part ?

Thanks

Jian Gao